What are MOLAP and ROLAP? - Data warehousing<

What are MOLAP and ROLAP?

Multidimensional Online Analytical Processing and Relational Online Analytical Processing are tools used in analysis of data which is multidimensional. ROLAP does not require the data to be computed beforehand. ROLAP access the Relational database and uses SQL queries for user requests. MOLAP on the other hand, requires the data to be computed before hand. The data is stored in a multidimensional array.

What are MOLAP and ROLAP?

MOLAP: A more traditional way of OLAP analysis. Data is persisted in a multidimensional cube in MOLAP. The storage is in proprietary formats but not in the relational database. MOLAP data cubes are built in such a way that data retrieval is faster and are optimal for dicing and slicing operations.

ROLAP: A methodology that is relied on manipulating the persisted data in the relational database, for providing an appearance of traditional OLAP’s dicing and slicing functionality. The actions of slicing and dicing are equivalent to adding the ‘WHERE’ clause in the SQL statement, is the essential part of ROLAP. The amount of data is not limited by ROLAP itself, thus able to handle large amounts of data..
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